10 crayons cost $9.50. Which equation would help determine the cost of 11 crayons?
There are several equations that could help determine the cost, each with a slightly different approach. We know the cost of 10 crayons. We want to know the cost of 11 crayons. We can write the numbers of crayons as a proportion: $\dfrac{10}{11}$ We know 10 crayons costs $9.50. We can let $x$ represent the unknown cost of 11 crayons. The proportion of these costs can be expressed as: $\dfrac{\$9.50}{x}$ The cost changes along with the number of crayons purchased, and so the two proportions are equivalent. $\dfrac{10}{11} = \dfrac{\$9.50}{x}$